According to the American Cancer Society, there were approximately 1,372,910 new cancer cases in 2005, with an additional 1 million cases of basal and squamous cell skin cancers in that same period. The five-year survival rate for cancer diagnosed between 1995 and 2000 was 64%, primarily due to improved methods of treatment and early detection. Still, over one-third of cancer patients were not expected to survive for five years, and a significant percentage of those who would survive for five years would have a recurrence of cancer, leading to a decreased survival rate at ten years and beyond.
Most academic research institutions and many pharmaceutical companies around the world have multiple oncology research programs focused on the development of new cancer-fighting agents, and the number of new compounds synthesized each year is considerable. There still remains a need, however, for agents that combat various forms of cancer and there is a special need for agents that are selective for cancer cells while sparing normal cells from damage.